Flexible packaging structure

ABSTRACT

The invention comprises a packaging structure which hermetically encloses a product prior to initial opening. The packaging structure comprises a line of weakness which defines a removable portion and a marginal region circumscribing the removable portion. A flap having a central region and a peripheral region is affixed to the packaging structure. At least a portion of the central region of the flap is affixed to the packaging structure via permanent adhesive and is aligned with the removable portion of the packaging structure. The peripheral region of the flap is affixed to the packaging structure via peelable adhesive and is aligned with the marginal region of the packaging structure.

BACKGROUND OF THE INVENTION

This invention relates to flexible packaging for products, and particularly relates to methods for making such packaging that is reclosable after initial opening.

A variety of food and non-food products are packaged using flexible packaging materials formed primarily of laminations of one or more of polymer films, metallized polymer films, paper, metal foil, and the like. In many instances, packages contain products that may be used or consumed a little at a time, and the products may be susceptible to being adversely affected (e.g., becoming soggy, drying out, etc.) by exposure to the surrounding environment. Accordingly, there is frequently a desire to maintain hermeticity of the package prior to opening as well as be able to reclose a package after its initial opening to keep product that remains in the package fresh.

Various opening and reclose arrangements have been developed for flexible packaging. Often, reclosability is achieved by using a peelable and resealable pressure sensitive adhesive (“PSA”) label that is attached to the exterior of the package adjacent the location where the package is opened. Such labels are formed separately from the packaging structure itself and are added to the packaging structure. However, in many cases, the packaging structure itself comprises an aperture beneath the adhesive label and the pressure sensitive adhesive label cannot ensure hermeticity prior to initial opening. In packages where the products disposed therein contain alcohol or a similar solvent (i.e. wet wipes), the solvent may evaporate if there is a lack of hermeticity. Further, the solvent may attack the pressure sensitive adhesive, destroying the functionality thereof, if the solvent is not hermetically separated from the pressure sensitive adhesive.

Through ingenuity and hard work, the inventors have developed a packaging structure having an external peelable and resealable pressure sensitive adhesive label, which maintaining the hermeticity of the products contained therein prior to initial opening of the package.

BRIEF SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, the invention comprises a packaging structure which hermetically encloses a product prior to initial opening. The packaging structure comprises a line of weakness which defines a removable portion and a marginal region circumscribing the removable portion. A flap having a central region and a peripheral region is affixed to the packaging structure. At least a portion of the central region of the flap is affixed to the packaging structure via permanent adhesive and is aligned with the removable portion of the packaging structure. The peripheral region of the flap is affixed to the packaging structure via peelable adhesive and is aligned with the marginal region of the packaging structure.

In another aspect, the invention comprises a packaging structure which hermetically encloses a product prior to initial opening, the packaging structure comprising a line of weakness which defines a removable portion and a marginal region circumscribing the removable portion. In such embodiment, the package comprises an adhesive layer comprising patterned permanent adhesive and patterned resealable adhesive and a flap affixed to the packaging structure via the adhesive layer. In this embodiment, the flap comprises a central region and a peripheral region and the central region of the flap is affixed to the packaging structure via the permanent adhesive and extends about the removable portion of the packaging structure. In this embodiment, the peripheral region of the flap is affixed to the packaging structure via the peelable adhesive and extends about the marginal region of the packaging structure.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 is a bottom view of a flap in accordance with embodiments of the invention;

FIG. 2 is a top view of a packaging structure in accordance with embodiments of the invention;

FIG. 3 is a perspective view of a package in accordance with embodiments of the invention; and

FIGS. 4 and 5 are cross-sectional view of a package in accordance with embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which some but not all embodiments of the invention are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

In an embodiment, the invention generally comprises a flexible packaging structure for food (i.e., cookies, crackers) or non-food products (i.e., tissues, wet wipes). The packaging structure may comprise a multi-layer laminate in an embodiment, wherein each of the layers comprises flexible material(s) such as polymer film, paper, barrier layers, metal foil, coatings, and combinations thereof. In an embodiment, the packaging structure and/or the flap may comprise a two-ply film, such as a machine-direction oriented print web film comprising two plies of polyethylene. In other embodiments, the packaging structure and/or the flap may include one or more layers of polyethylene terephthalate (PET), oriented polypropylene (OPP), polyethylene (PE), polypropylene (PP), polylactic acid (PLA), sealant, ink or print, nylon, and/or a metalized layer, such as a metalized oriented polypropylene (MET OPP) layer, as a few examples. In an embodiment, the packaging structure and/or the flap comprise a paper layer and a polymeric layer. In other embodiments, the packaging structure and/or the flap may comprise a single layer. In an embodiment, the packaging structure is hermetic prior to being opened. In an embodiment, the packaging structure is completely hermetic prior to being opened. In an embodiment, a separate flap is adhered to the packaging structure. In such embodiment, the flap may be adhered to the packaging structure with a PSA to provide reclosability for the package. In other embodiments, a combination of pattern-applied permanent adhesive, semi-permanent adhesive, high bond strength adhesive, aggressive adhesive, and/or PSA may be used to adhere the flap to the packaging structure.

In an embodiment, the packaging structure may comprise a flow wrap configuration, which may employ a continuous film or web to envelop a product during assembly or formation of the package. Flow-wrap packages may include, for example, horizontal or vertical fin seal or lap seal packages, end seal wrap, horizontal bagging and pillow-pouch packaging. In one configuration, flow-wrap packaging positions a film, such as polyethylene or polypropylene, adjacent a product, wraps the film around the product, forms a fin or lap seal from the ends or edges of the film, and then forms end seals at either end of the product. These seals may be permanent and also may provide some structural integrity. These seals may be formed by a variety of process such as, for example, hot seal, cold seal, low tack seal such as that employing a low tack adhesive or fastener, sonic waves, and combinations thereof.

The flexible film packages may have a variety of configurations, including, for example, a bag, a pouch, or other shapes such as a cylindrical-shape, a column-shape, or a rectilinear-shape, among others. For example, the flexible film package may have squared edges such as that found on a primarily rectilinear-shaped package, or may have more curvilinear-shaped edges, such as that found on more circular or ovoid-shaped packages. Further, the flexible film package may be formed around a product, such as a package having a tubular configuration that is wrapped around a discrete stack of products. In other applications, the flexible film packages may be fully or partially formed and then filled with the products, which may be helpful for various discrete products. The various configurations may be easily opened and resealed while maintaining package integrity.

In an embodiment, the packaging structure may have a line of weakness that maintains hermeticity prior to package opening, but defines a package opening upon initial rupture. Upon rupture, the packaging structure material disposed within the perimeter of the line of weakness may be lifted out of the plane of the packaging structure, as it is adhered to the flap. That is, the line of weakness allows a tear to propagate through the surface of the hermetically sealed package when the package is opened. The line of weakness may comprise a score line that extends partially into, but not completely through, the packaging structure. For example, the line of weakness may extend about 50%-80%, or 60%-80%, or 70-80% of the way through the packaging structure. In an embodiment, the line of weakness may extend into the packaging structure by up to about 80% of the thickness of the packaging structure. The packaging structure may be scored on its internal surface or its external surface (relative to the product contained therein).

In some embodiments, wherein the packaging structure is adhered to the flap prior to formation of the line of weakness, the line of weakness may extend through the packaging structure but does not extend through a sealant layer or an adhesive layer disposed between the packaging structure and the flap, such that the sealant layer or adhesive layer is configured to maintain the hermeticity of the package. In some embodiments, the line of weakness may extend partially into the sealant layer or adhesive layer.

Alternatively, the film packaging structure could be stressed or damaged (i.e., via an electron-beam treatment to weaken the film) in a manner that creates a line of weakness and allows a tear to propagate in a controlled manner when the package is opened. Because the line of weakness is not scored as a throughcut, it preserves the hermeticity of the package prior to initial opening. That is, even with the line of weakness formed in the packaging structure, the packaging structure is hermetically sealed prior to initial opening thereof.

In an embodiment, the package comprises a flap. The flap may be provided, in the manufacturing process, with a backing, release liner or may be a linerless label. In one embodiment, the flap is applied to the packaging structure and extends over the line of weakness. The flap may have an unadhered pull tab used to separate the flap from the packaging structure and rupture the packaging structure to form the package opening. The packaging structure and flap will now be explained in greater detail with reference to the drawings.

In an embodiment shown in FIG. 1 , the flap 100 comprises a peripheral region 110 and a central region 112. In an embodiment, the peripheral region 110 circumvents the central region 112. In an embodiment, the central region 112 may have a regular shape, such as a circle, oval, rectangle, square, or other shape. In other embodiments, the central region 112 may be irregularly shaped. An interface 114 may be disposed between the peripheral region 110 and the central region 112.

In an embodiment, the peripheral region 110 may be coated with a peelable and, optionally, resealable adhesive 120 on a first surface 100 a thereof (see cross-section in FIG. 4 ). In an embodiment, the adhesive 120 used in the peripheral region 110 may comprise a weak adhesive or a PSA. After initial lifting of the flap 100 and rupture of the underlying packaging structure via the line of weakness 210, the resulting opening may be reclosed by adhering the peripheral region 110 of the flap 100 to the underlying portion of the packaging structure via the pressure-sensitive adhesive 120. The width of the peripheral region 110 may be sufficient to effectively reseal the flap 100 to the underlying container structure once the line of weakness 210 has been ruptured.

The PSA can comprise various compositions. PSAs form viscoelastic bonds that are aggressively and permanently tacky, adhere without the need of more than a finger or hand pressure, and require no activation by water, solvent or heat. PSAs are often based on non-crosslinked rubber adhesives in a latex emulsion or solvent-borne form, or can comprise acrylic and methacrylate adhesives, styrene copolymers (SIS/SBS), and silicones. Acrylic adhesives are known for excellent environmental resistance and fast-setting time when compared with other resin systems. Acrylic pressure-sensitive adhesives often use an acrylate system. Natural rubber, synthetic rubber or elastomer sealants and adhesives can be based on a variety of systems such as silicone, polyurethane, chloroprene, butyl, polybutadiene, isoprene, or neoprene. When the packaging laminate of the invention is to be used for food packaging, the PSA generally must be a food-grade composition. Additives (e.g., particulates or the like) can be added to the PSA to reduce the tenacity of the bond to the underlying structure, if desired, so that the PSA readily detaches from the underlying structure on opening (particularly on the very first opening). In an embodiment, the PSA may be applied throughout the peripheral region 110, but in other embodiments, the PSA may be applied in a pattern within or about the peripheral region. For example, the PSA may be applied in one or more concentric circles, a pattern of dots, a pattern of stripes or lines, etc.

In an embodiment, the central region 112 may be coated with a permanent adhesive, semi-permanent adhesive, high bond strength adhesive, aggressive pressure sensitive adhesive, or similar adhesive 122 (which may or may not be a PSA) on the first surface 100 a thereof. Such adhesives may be generally referred to herein as “permanent” adhesives. It should be understood that while the adhesives 122 are describes as being coated onto the flap 100, the inventor contemplates coating the adhesive(s) onto the packaging film material as an alternative, using adhesives that are applied in manners other than coating, and the like. One of ordinary skill in the art would understand such applications. The adhesive(s) may be applied using any suitable equipment and technique, such as by a gravure roll or the like.

In an embodiment, the flap 100 additionally comprises a pull tab 116. The pull tab 116 may extend from the peripheral region 110, in an embodiment and may be configured for gripping to pull the flap 100 away from the packaging structure. In an embodiment, the pull tab 116 is free of adhesive. In an embodiment, a distal portion 118 of the flap 100, opposite the pull tab 116, is coated with a permanent adhesive 122 a, such that it can be permanently adhered to the packaging structure 200. In this embodiment, the flap 100 is less likely to be inadvertently misplaced for reclosure. In other embodiments, the flap 100 may be completely removable from the packaging structure 200. This embodiment may be helpful for packages that are not intended to be reclosed.

FIG. 2 illustrates a top view of an exemplary packaging structure 200 of the invention. In this embodiment, the packaging structure may comprise two end seals 212 and a lap or fin seal (not shown, on opposite side). In an embodiment, the packaging structure 200 additionally comprises a line of weakness 210, as described more fully above. In the embodiment shown in FIG. 2 , the label 100 has not been applied to the packaging structure 200. The line of weakness 210 may be formed by laser scoring, mechanical scoring or cutting, such as by die cutting or kiss cutting, or via any other method known in the art. In an embodiment, the line of weakness 210 may have a regular shape, such as a circle, oval, rectangle, square, or other shape. In other embodiments, the line of weakness 210 may be irregularly shaped. In an embodiment, the line of weakness 210 and the interface 114 between the central portion 112 and the peripheral portion 110 are sized and configured to be the same. That is, if the line of weakness 210 is an oval, the interface 114 also comprises an oval of the same size or approximately the same size. The removable portion 214 of the packaging structure 200 is defined by the line of weakness 210.

In an embodiment, the inner surface of the packaging structure 200 may include a sealant layer or coating. The sealant layer or coating may comprise a heat seal material such as polyethylene, polypropylene, ionomer resin such as SURLYN®, or the like, or a cold seal material. The packaging structure 200 may also include a barrier layer providing a barrier against the passage of moisture and/or oxygen. In some applications such as the packaging of moisture-sensitive products, it is important to provide a moisture barrier. The barrier layer can comprise any of various polymer-based barrier materials including barrier polymer films such as ethylene vinyl alcohol copolymer (EVOH), polyamide, and the like; metallized polyolefin films such as polyethylene, polypropylene, oriented polypropylene, and the like; AlOx-coated polymer films; SiOx-coated polymer films; metal foil such as aluminum foil; and others. Although the term “barrier layer” is used in connection with metallized films to refer to the entire metallized film, it will be recognized that it is the layer of metal that provides the barrier function. Likewise, it is the AlOx or SiOx coating that provides the barrier function in the ceramic-coated films, but the entire film nevertheless is referred to herein as a “barrier layer”.

One or more of the layers of the packaging structure 200 may be treated by a corona discharge or flame treatment apparatus to render the surface more-receptive to the inks and/or to render the surface more-readily bondable to the pressure-sensitive adhesive that is subsequently pattern-applied to the surface.

FIG. 3 illustrates a perspective view of a package 300 comprising the packaging structure 200 and an adhered flap 100. The packaging structure 200 envelopes the package contents and is sealed to enclose the contents. A sheet (optionally a laminate sheet) is manipulated into a tubular shape and the longitudinal edges of the wrapper are sealed together by a suitable sealant material to form a longitudinal seal (not shown), typically adjacent the bottom surface of the package. The opposing portions of the packaging structure 200 are sealed together along transverse seal lines adjacent the opposite ends of the tubular wrapper to form end seals 212. The ends of the wrapper can be gusseted if desired, as known in the art.

In the illustrated package 300, the portion of the packaging structure 200 having the line of weakness 210 and flap 100 is provided to be on the top surface of the package. The area of the packaging structure 200 bounded by the line of weakness 210 and flap 100 can constitute any fraction of the total top surface of the package, but advantageously the area is a majority of the total surface area of the top surface. In other embodiments, the line of weakness 210 and flap 100 may be provided on a side surface of the package (such as in a pouch structure), on a bottom surface, on a front surface, or any other surface known in the art.

As shown in FIG. 4 , the line of weakness 210 and the interface 114 of the flap 100 which is disposed between the peripheral region 110 and the central region 112, are aligned. This alignment may be exact or approximate. For example, the line of weakness 210 may be slightly outside (see FIG. 5 ) or slightly inside the interface 114.

With reference to FIGS. 3 and 4 , the package 300 is shown in a closed condition, for example as initially filled and sealed in a packaging plant. On the top surface of the packaging structure 200, the packaging structure 200 is adhesively joined to the flap 100 via the permanent adhesive 122 and peelable and/or resealable adhesive 120. The packaging structure 200 has a marginal region 220 disposed peripherally around the line of weakness 210. In an embodiment, the marginal region 220 of the packaging structure is aligned with the PSA region 120. In an embodiment, the removable portion 214 of the packaging structure 200 is aligned with the permanent adhesive 122. The removable portion 214 of the packaging structure 200 and the central region 112 of the flap 100 are permanently joined by the permanent adhesive 122.

In some embodiments, the entire central region 112 is permanently joined to the removable portion 214, while in other embodiments, only a portion of the central region 112 is permanently joined to the removal portion 214. In these embodiments, the permanent adhesive 122 may be applied in a pattern, such as one or more concentric circles, a series of dots, lines, stripes, or the like. Such a pattern of adhesive may ensure a permanent joining of the layers with less adhesive.

Consequently, when the flap 100 is peeled back from the packaging structure 200, the line of weakness 210 ruptures and the removable portion 214 of the packaging structure 200 remains affixed to the central region 112 of the flap 100, thereby creating an opening in the top surface of the packaging structure 200. The flap 100 may be completely removed from the packaging structure or may be affixed at the distal portion 118 via permanent adhesive 122 a.

The flap 100 preferably has a greater affinity for bonding with the PSA 120 than does the surface of the marginal region 220 of the packaging structure 200, and hence the PSA 120 is detached from the surface of the marginal region 220 and remains attached to the flap 100. The package is reclosable by re-attaching the PSA 120 to the marginal region 220 of the packaging structure 200 to restore the package to its closed condition.

The greater bonding affinity of the flap 100 can be achieved in various ways. When the flap 100 comprises a layer of PET and the surface of the packaging structure 200 comprises a polyolefin such as polypropylene, oriented polypropylene, or metallized oriented polypropylene, the PET will naturally have a greater affinity for bonding to the adhesive than will the polyolefin layer. Additionally or alternatively, the inner surface 100 a of the flap 100 may be treated, as previously noted, by corona discharge or flame treatment, to increase the surface energy and enhance the bonding affinity. It is also possible, as noted, to control the bond strength of the PSA by including an additive in the adhesive to reduce the bond strength, if desired.

Although the PSA 120 and permanent adhesive 122 are disclosed herein as being applied to the flap 100 and the PSA 120 is disclosed as remaining on the flap 100 upon opening of the package, it is also within the scope of the invention to apply the PSA 120 and/or permanent adhesive 122 to the packaging structure 200 and for the PSA 120 to remain on the packaging structure 200 upon opening of the package. One of skill in the art would understand that there are many ways to accomplish the adhesive features of the invention. For example, the PSA could be flood coated over the flap, followed by a pattern application of permanent adhesive over the top of the PSA, in the central region. Likewise, an aggressive PSA could be flood coated over the flap, followed by a pattern partial deactivation of the PSA, in the central region.

It will be appreciated from the above description that laminates made in accordance with the invention inherently provide a tamper-evidence function for a package because after opening, the line of weakness 210 is ruptured. Thus, it is readily ascertainable that the package has been opened.

The packages described above are formed by completely enveloping the contents in the packaging structure 200. Alternatively, however, it is within the scope of the invention to employ the flexible laminate as a lidding stock for forming flexible lids that can be secured (e.g., by heat-sealing or the like) to a flange of a tray or other container that contains the contents.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 

What is claimed is:
 1. A package comprising: a packaging structure which hermetically encloses a product prior to initial opening, the packaging structure comprising a line of weakness which defines a removable portion and a marginal region circumscribing the removable portion; an adhesive layer comprising permanent adhesive and peelable adhesive; and a flap affixed to the packaging structure via the adhesive layer, wherein: the flap comprises a central region and a peripheral region; at least a portion of the central region of the flap is affixed to the packaging structure via the permanent adhesive and is aligned with the removable portion of the packaging structure; and the peripheral region of the flap is affixed to the packaging structure via the peelable adhesive and is aligned with the marginal region of the packaging structure.
 2. The package of claim 1, wherein the peelable adhesive is a resealable adhesive.
 3. The package of claim 1, wherein the peelable adhesive comprises a pressure sensitive adhesive.
 4. The package of claim 1, wherein the line of weakness extends into, but not through the packaging structure.
 5. The package of claim 1, wherein the line of weakness extends into, but not through the adhesive layer.
 6. The package of claim 1, additionally comprising a sealant layer disposed between the packaging structure and the adhesive layer.
 7. The package of claim 6, wherein the line of weakness extends into, but not through the sealant layer.
 8. The package of claim 1, wherein the line of weakness is rupturable.
 9. The package of claim 1, wherein the line of weakness comprises a portion of the packaging structure which is stressed or damaged.
 10. The package of claim 1, wherein the line of weakness is formed via electron-beam treatment.
 11. The package of claim 1, wherein the line of weakness does not extend through the packaging structure.
 12. The package of claim 1, wherein the line of weakness defines a closed shape.
 13. The package of claim 1, wherein when the package is in an opened configuration, the peripheral region of the flap releases from the marginal region of the packaging structure and the removable portion of the packaging structure remains affixed to the central region of the flap as the flap is lifted out of the plane of the packaging structure.
 14. The package of claim 1, wherein when the package is in a reclosed configuration, the peripheral region of the flap readheres to the marginal region of the packaging structure.
 15. A package comprising: a packaging structure which hermetically encloses a product prior to initial opening, the packaging structure comprising a line of weakness which defines a removable portion and a marginal region circumscribing the removable portion; an adhesive layer comprising patterned permanent adhesive and patterned resealable adhesive; and a flap affixed to the packaging structure via the adhesive layer, wherein: the flap comprises a central region and a peripheral region; at least a portion of the central region of the flap is affixed to the packaging structure via the permanent adhesive and extends about the removable portion of the packaging structure; and the peripheral region of the flap is affixed to the packaging structure via the peelable adhesive and extends about the marginal region of the packaging structure.
 16. The package of claim 12, wherein the line of weakness is rupturable.
 17. The package of claim 12, wherein when the package is in an opened configuration, the peripheral region of the flap releases from the marginal region of the packaging structure and the removable portion of the packaging structure remains affixed to the central region of the flap as the flap is lifted out of the plane of the packaging structure.
 18. The package of claim 12, wherein when the package is in a reclosed configuration, the peripheral region of the flap readheres to the marginal region of the packaging structure.
 19. A package comprising: a packaging structure which hermetically encloses a product prior to initial opening, the packaging structure comprising a line of weakness which defines a removable portion and a marginal region circumscribing the removable portion; an adhesive layer comprising patterned permanent adhesive and pressure sensitive adhesive; and a flap affixed to the packaging structure via the adhesive layer, wherein: the flap comprises a central region and a peripheral region; at least a portion of the central region of the flap is affixed to the packaging structure via the permanent adhesive and is aligned with the removable portion of the packaging structure; and the peripheral region of the flap is affixed to the packaging structure via the peelable adhesive and is aligned with the marginal region of the packaging structure.
 20. The package of claim 16, wherein the line of weakness is rupturable.
 21. The package of claim 16, wherein when the package is in an opened configuration, the peripheral region of the flap releases from the marginal region of the packaging structure and the central region of the flap remains affixed to the removable portion of the packaging structure.
 22. The package of claim 16, wherein when the package is in a reclosed configuration, the peripheral region of the flap readheres to the marginal region of the packaging structure. 